[n] the act of distinguishing by comparing differences
[n] (photography) the range of optical density and tone on a photographic negative or print (or the extent to which adjacent areas on a television screen differ in brightness)
[n] the perceptual effect of the juxtaposition of very different colors
[n] a conceptual separation or demarcation; "there is a narrow line between sanity and insanity"
[n] the opposition or dissimilarity of things that are compared; "in contrast to", "by contrast"
[v] put in opposition to show or emphasize differences; "The middle school teacher contrasted her best student's work with that of her weakest student"
[v] to show differences when compared; be different; "the students contrast considerably in their artistic abilities"